Here's a simple DIY that I just made a few hours ago:
First, grab a medium-sized wood panel or small pallet
This one here is from IKEA - my all time favorite store.
It came from their clearance room and cost me $1
(Needless to say, you can find pretty great things there!)
Then, grab some post-it letters and a favorite quote:
Since they only stick on the top, you'll also need some rubber cement glue (the most magical glue, in my opinion), so the paint doesn't creep under the letters.
Next, glue down your letters quickly as not to let the rubber cement dry too long.
After you have your words glued in place, grab some paint and a sponge brush and get to work. I recommend putting the paint directly on the sponge brush first, and twisting it around to even out the amount of paint on it.
Finally, after waiting a bit to let the paint dry, peel off the letters and touch-up the corners or sides that may have gotten paint under them.
Nail polish remover on a Q-tip works very well.
Now find a home for it and enjoy!